Screw or worm propeller for the propulsion of all kinds of craft for use in water and air



Oct. 23, 192 8. 1,688,639

. ?J. K. LARSON SCREW OR WORM PR PELLER FOR THE PROPULSION OF ALL KINDS OF CRAFT FOR USE IN WATER AND AIR Eiled Feb. 14, 1923 2 Sheets-Sheet 1 INVENTOR Oct. 23, 1928. 1,688,639

I J. K. LARSON SCREW OR WORM PROPELLER FOR THE PROPULS OF ALL KINDS FOR IN OF CRAFT USE WATER AN IR Filed Feb. 14, 1923 2 Sheets-Sheet 2 I INVENTOR Patented Oct. 23, 1928 UNITED STATES.

PATENT", OFFICE.

JOHN K, LARSON, OF PORTLAND, OREGON.

SCREW OR WORM PBOPELLER FOR THE PROPULSION OF ALL KINDS-OFCRAFT FOB USE IN WATERAND' AIR.

Application filed February 14, 1923. Serial No. 619,065.

This invention relates to impellers and more particularly to propellers of the screw or worm type which may be used for propulsion of land, air or marine vessels, and has for an object to provide a propeller of this particular type in which the blades are provided with means to reduce the skin friction without reducing the vacuum eflect of the propeller.

A further object is to provide a propeller of the screw or worm type in which stepped blades are used to reduce the skin friction and enable the motor to turn said blades faster with the same power without reducing the vacuum effect.

. A still further object is to provide a propeller of this type having flanged edges over which the fluid may break.

IVith these and other objects in view, my invention consists in certain novel features of construction, arrangement and combination of parts as will be hereinafter fully described and pointed out in the claims, reference being had to the accompanying drawings, in which Figure 1 is a side elevation of one developmerit of the inventive idea involved,

Figure 2 is a similar view showing a form in which one face of the blade isstepped,

Figure 3 is a similar View of a form in which both faces of the blade are stepped,

Figure 4 is a side elevation of another form of the invention.

Figure 5 is an elevational view showing a blade provided with side flanges,

Figure 6 is a similar view showing a blade with one side edge only flanged,

Figure 7 is a view similar to Figures 5 and 6 showing another arrangement of arms or spokes for connecting the blade with the hub.

Referring more particularly to Figure 1 of the drawings, A represents a single screw or worm propeller blade of the plane type, and is provided with smooth curved surfaces all all sides making one complete circle. These blades may be of solid construction, or rigidly attached to arms or spokes D which have less pitch than the propeller blades, and which radiate from the hubs C through which is passed the shaft B and to which they are rigidly fixed by key, set screw, or otherwise.

In Figure 2 the blade is provided with smooth curved lines A on one side and a stepped surface A on the: working face.

This blade is connected to the shaft by the arms or spokes D radiating from the hubs C, which may be secured to shaft B, as above set forth.

In Figure 3 the blade is provided with step blades A A on both faces, and is either of solid construction or is rigidly attached to shaft B through arms or spokes D and hubs G which latter are secured to said shaft in any suitable manner. There is no restriction on the number or depth of steps, as there i vacuum as possible, which is the secret of,

power, that is, the vacuum effect obtained by the least skin friction or wetted surface to be forced against the water bymotive power.

By my construction and arrangement I minimize wetted surfaces and skin friction by the use of step power blades of various heights, lengths and curved lines, suitable for the different classes of work to be performed by the propeller.

In Figure 4 the propeller is of the double blade type, and these blades A which are supported by arms or spokes D extending from the hubs C which are to be rigidly secured to shaft B in any suitable manner.

The blades in Figures 1,2, 3 and 4: may have I-beam reinforcements as indicated in Figures 5, 6 and 7; that is, like Figure 5 with I- beam reinforcements on both edges the propeller blade A which is rigidly connected with its shaft through arm or spoke D and The blades shown in Figures 5, 6 and 7 form segments or parts of a Whole circle for the short screw or Worm shaped propeller blade for the three and four-bladed propel- 5 ler Wheels.

Any or all of the above described propellers can be used as a surface marine propeller by locating the shafts slightly about the Water line; this form being practical in tWin screws 10 each propeller turning in opposite directions.

I claim 1. A propeller of the screw or Worm type,

v the said opposite faces.

comprising a supporting shaft, a pitched spiral blade and pitched spokes having less pitch than the blade, the opposite faces of said blade having a plurality of transverse stepped portions of material length and Width.

2. A propeller as set forth in claim 1, char acterized by the transverse shoulders defined by the stepped portions disposed in overlapping relation longitudinally of the blades on J. K. LARSON. 

